Ex parte Boyd is a United States Supreme Court case that dealt with the issue of whether a state court could issue a writ of habeas corpus to a federal prisoner. The case involved a man named Boyd, who was convicted of a federal crime and sentenced to prison. He then filed a petition for a writ of habeas corpus in a state court, arguing that his conviction was unconstitutional. The state court granted the writ, and Boyd was released from prison. The United States government then appealed the decision to the Supreme Court, arguing that the state court had no authority to issue a writ of habeas corpus to a federal prisoner. The Supreme Court agreed, ruling that the state court had no jurisdiction to issue the writ. The Court held that the power to issue writs of habeas corpus was exclusively vested in the federal government, and that state courts could not interfere with federal criminal proceedings. The Court also held that the writ of habeas corpus could only be issued by a federal court, and that state courts had no authority to issue such writs.

In Ex Parte Boyd, the Supreme Court was asked to decide whether a federal court had jurisdiction over a case involving an alleged violation of the Civil Rights Act. The majority opinion held that it did not have such jurisdiction because the act only applied to state action and this case involved private parties. Justice Field dissented from this decision, arguing that Congress had intended for federal courts to have jurisdiction in cases like these. He argued that since Congress had passed laws allowing citizens to bring suits against individuals who violated their civil rights, then it would be illogical for them not to provide access through federal courts as well. Furthermore, he noted that if there were no remedy available through federal courts then those seeking justice would be left without any recourse at all. In conclusion, Justice Field believed that Congress clearly intended for federal courts to have jurisdiction over civil rights violations regardless of whether they involved public or private actors and thus should be allowed in this instance as well.